In typical procedures for studying gel materials, such materials have been frozen, and then sliced into uniform segments for use as samples for study. Previously employed gel slicing devices have not been able to produce satisfactorily uniform slices, are slow in operation, and been limited to slices either of only one thickness or to arrangements wherein it is very difficult to vary the slice thickness and at the same time maintain uniformity of the adjusted slice thickness. In most of the prior gel slicing devices the apparatus is hand-operated, limiting the slicing speed and making it difficult to insure slicing accuracy. Although feed screws have been employed for advancing the gel material into slicing position, there has not been accurate coordination between the operation of the feed screw and the slice-cutting blade, so that it has been difficult to obtain adequate uniformity of slice thickness with reasonably rapid slicing action.
Accordingly, there is a definite need for an automated gel slicing apparatus wherein the slice thickness is accurately maintained, wherein it is easy to load the apparatus with gel material to be sliced, wherein the apparatus can be easily adjusted to obtain a desired slice thickness, and wherein there is accurate and reliable coordination between the feed screw and the slice cutting blade in any one of the adjusted slice thickness conditions.
A number of commercial gel slicers are presently available, but these all suffer from one or more of the deficiencies mentioned above. These include the Mickle Gel Slicer (Brinkman Instruments, Inc.); the Lateral Gel Slicer (Ames Company, Miles Division of Miles Laboratories); the Macrotome GTS (Linca Lamon Instrumentation Co., Ltd.); and the Bio-Rad Gel Slicer Model 190 and Bio-Rad Electric Gel Slicer Model 195 (Bio-Rad Laboratories). Patented devices, also deficient in one or more of the afore-mentioned ways, are shown in Schaffer et al U.S. Pat. No. 3,807,604; Farquhar et al U.S. Pat. No. 3,420,130; Blum U.S. Pat. No. 3,496,819 and Ordman U.S. Pat. No. 2,186,878.